Trigger/disconnector assembly for AR-7 survival rifle

ABSTRACT

A method for retrofitting a rifle having an integral trigger/disconnector. The method comprises the steps of: removing the integral trigger/disconnector; and installing an assembly comprising a spring-loaded disconnector and a trigger in place of the integral trigger/disconnector. The spring-loaded disconnector is able to move to the rear when contacted by the hammer to allow the hammer to pass, and then quickly return to its forward position so as to capture the hammer.

BACKGROUND OF THE INVENTION

This invention relates in general to firearms, and in particular to relatively small, lightweight rifles that are primarily intended for survival use in emergency situations.

The term “survival rifle” is commonly used in referring to a firearm that is primarily intended for use as a personal survival weapon in unforeseen or emergency situations. Persons such as campers, boaters, or flyers who travel through or over wilderness locations may not want to carry a conventional rifle due to its weight and size, but those persons may nonetheless want a weapon of greater accuracy than a handgun for hunting small game or for personal protection if they suddenly become stranded in the wilderness by a mishap such as a downed airplane or a broken vehicle. The ideal survival rifle should be relatively lightweight and compact, so as not to add significant weight to a backpacker and so as to conveniently fit within a pack, a small airplane, or in some other location not normally sized to receive a conventional rifle. A survival rifle should also be relatively inexpensive to manufacture, and should be capable of quick and easy assembly by the user without requiring tools or connective parts such as bolts that can easily become lost in the field. The survival rifle should also be capable of carrying a supply of ammunition.

Attempts have been made in the prior art to produce survival rifles that meet some of the foregoing criteria. Known examples of such prior art include the U.S. Air Force (USAF) M4 .22 Hornet bolt action rifle, the USAF M6 .22/.410 over/under survival rifle, the Armalite/Charter Arms AR-7 .22 semiautomatic survival rifle, and the Garcia “Bronco” single-shot survival rifle with a skeleton stock.

The AR-7 type rifle is a takedown survival rifle that was intended for use by pilots who have been shot down and subsequently parachuted into non-friendly territory. It was originally designed in 1959 for the U.S. Air Force by Armalite and has been manufactured by Charter Arms. It was not intended to be a main combat weapon but rather as a hunting survival weapon. The AR-7 model rifle fires the .22 long rifle ammunition in semiautomatic mode. FIG. 11 shows an AR-7 model rifle 50 comprising a receiver 52, a barrel 54 that is removably coupled to the receiver by means of a barrel nut 60, a magazine 62 inserted into the receiver, a shoulder stock 56 attached to the receiver and having a compartment, and a cover 58 that is press fit over the butt end of the shoulder stock to close the compartment. The term “takedown” is used to describe any firearm design in which the barrel may rapidly be removed in order to make the firearm more portable and/or effect compact storage. The AR-7 model rifle can be broken down and reassembled without tools. Broken down, the parts may be conveniently stored in the compartment built into the shoulder stock 56 (the parts do not fit entirely within the compartment but rather protrude outside).

Being that the AR-7 was considered a survival rifle, the design was rudimentary. The main design defect of the AR-7 rifle was the lack of a mechanical disconnector. This lack of a mechanical disconnector/trigger assembly causes undue friction and force to be necessary to effect operation of the components as they were originally designed. This design defect causes a condition known as short recoil. The term “short recoil” is used to describe a malfunction with a semi-automatic firearm. When short recoil occurs, the bolt (for any one of a number of reasons) fails to move sufficiently to the rear to complete its cycle of operation. The short recoil causes malfunctions commonly known as jams.

The AR-7 rifle is a blowback-operated semi-automatic rifle. Upon firing, the bullet is forced through the barrel while at the same time the bolt, utilizing the pressure of the fired cartridge, is forced to the rear and through its cycle of operation. In this system of operation, there is no locking mechanism employed. During the firing sequence, the trigger is depressed, which causes the hammer to be released. The hammer, under spring pressure, is then rapidly driven forward to contact the firing pin and cause discharge. Upon discharge, the bolt, utilizing the recoil energy of the fired cartridge, is driven rearward, also driving the hammer rearward. At this point in the sequence, the trigger is still depressed, as this all happens very quickly (in less than ¼ of a second). In the AR-7 rifle, the pivoting of the trigger during depression causes a hook located at the rearward portion of the trigger to come into the path of the rebounding hammer. This hook captures the hammer by means of a notch cut into the rearward section of the hammer. This hook is known as the “disconnector”.

The function of the disconnector is to capture the hammer during its rearward travel and hold it until the trigger is released after firing. When the trigger is released, the trigger pivots forward, causing the hook to rotate backwards, releasing the hammer. The hammer coil spring again urges the released hammer to rotate forward. The hammer's forward travel will be stopped when it is once again captured by the trigger nose (i.e., sear), which engages the sear notch of the hammer.

On the original AR-7 design, the disconnector hook is integral with the trigger. In order for the disconnector hook to capture the hammer, the trigger must be forced to pivot forward to allow clearance for this to occur. This forces the finger of the shooter to be rapidly pushed forward. If the shooter were to hold the trigger depressed hard enough, the disconnector hook will not be able to cause the trigger to pivot forward and allow sufficient clearance for the hammer to pass the disconnector hook and be captured by same. This is due to the fact that the disconnector hook and the trigger are integral.

There is a need for a solution to the foregoing problem in existing AR-7 rifles. More specifically, there is a need for a redesign of the AR-7 components to eliminate the problem of short recoil.

BRIEF DESCRIPTION OF THE INVENTION

The present invention is directed to providing a solution to the problem of short recoil in AR-7 rifles. The problem is solved by providing a multiple-component trigger/disconnector assembly. This assembly employs a separate disconnector hook that operates in conjunction with the trigger. The trigger/disconnector assembly can be retrofitted into existing AR-7 rifles, thereby greatly enhancing their functionality. This retrofit is designed to allow existing AR-7 rifles to be readily converted to the system disclosed herein.

One aspect of the invention is an AR-7 rifle having a firing mechanism comprising: a hammer that pivots on a first pivot pin, a trigger that pivots on a second pivot pin; the trigger comprising a sear that holds the hammer in a first captured rearward position before the rifle is fired; a spring that causes the hammer to pivot forward when the hammer is released from the first captured rearward position, and a disconnector coupled to the trigger in a manner that allows the disconnector to displace relative to the trigger, the disconnector comprising a hook that captures the hammer in a second captured rearward position during recoil after the rifle has been fired.

Another aspect of the invention is a method for retrofitting a rifle having an integral trigger/disconnector, comprising the steps of: removing the integral trigger/disconnector; and installing an assembly comprising a disconnector and a trigger in place of the integral trigger/disconnector, the disconnector being displaceable relative to the trigger.

A further aspect of the invention is a method for installing a firing mechanism in a receiver of an AR-7 model rifle, comprising the steps of: making a trigger having top portion with a recess bounded on opposing sides by first and second walls, the first and second walls having first and second apertures respectively, the first and second apertures being aligned with each other; making a disconnector having a slot that will overlap the first and second apertures when a bottom portion of the disconnector is inserted into the recess with a predetermined positional relationship; inserting the bottom portion of the disconnector into the recess with that predetermined positional relationship; inserting a pin through the first and second apertures and the slot; fixing the pin to the trigger on both sides of the recess, thereby coupling the disconnector to the trigger; and installing the coupled disconnector/trigger in a receiver of an AR-7 model rifle.

Yet another aspect of the invention is an assembly comprising: a trigger having a rearward portion with a recess bounded on opposing sides by first and second walls and having a flat bottom, the first and second walls having first and second apertures respectively, the first and second apertures having the same diameter and being aligned with each other; a disconnector having a bottom portion inserted in the recess in the rearward portion of the trigger, the disconnector having a slot that overlaps the first and second apertures, the slot having a length greater than the diameter of the first and second apertures, the disconnector comprising a bottom straight edge running parallel to a length direction of the slot; a retainer pin that passes through the first and second apertures and the slot, and projects beyond the first and second walls on respective sides of the rearward portion, and a coil spring seated at one end against a portion of the trigger and seated at the other end against a portion of the disconnector, the coil spring urging the disconnector to displace in the recess relative to the trigger.

Other aspects of the invention are disclosed and claimed below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing showing a side view of a firing mechanism in a conventional AR-7 model rifle.

FIGS. 2 and 3 are drawings showing respective side views of a firing mechanism for an AR-7 model rifle in accordance with one embodiment of the present invention. FIG. 2 shows the hammer in a first angular position whereat it is captured by a sear at the trigger nose, while FIG. 3 shows the hammer in a second angular position whereat it is captured by a disconnector hook.

FIGS. 4-6 are drawings showing side, front and top views respectively of the trigger incorporated in the embodiment depicted in FIGS. 2 and 3.

FIGS. 7-9 are drawings showing side, front and bottom views respectively of the disconnector incorporated in the embodiment depicted in FIGS. 2 and 3.

FIG. 10 is a drawing showing a side view of the hammer incorporated in the embodiment depicted in FIGS. 2 and 3.

FIG. 11 is a drawing showing a side view of a conventional AR-7 model rifle fully assembled.

Reference will now be made to the drawings in which similar elements in different drawings bear the same reference numerals.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a firing mechanism of the type currently incorporated in the AR-7 model rifle. The firing mechanism comprises a hammer 6 that slides over and is pivotably mounted to a pivot pin 8 and an integral trigger/disconnector 24 that slides over and is pivotably mounted to a pivot pin 4. Both pivot pins have one end inserted in a respective blind hole in the back wall of a receiver (not shown in FIG. 1). The free ends of those pivot pins are in turn blocked by the receiver side plate when it is installed, which prevents the pivot pins from coming out of their respective blind holes. The integral component 24 comprises a trigger 2 and a disconnector in the shape of a hook 18. The integral component has a second hole (the first hole receives the trigger pivot pin) that receives a retainer pin 22 that projects outward on both sides of the integral component 24. The projecting ends of the retainer pin 22 anchor the respective ends of a hammer spring 21 this is wound around the opposing ends of hammer pivot pin 8 and wrapped around a bottom edge of the hammer 6. Only one half of the hammer spring 21 is visible in FIG. 1. The hammer spring wraps around both sides of the hammer to provide forward spring force on the hammer. The opposite ends of the hammer spring 21 bear on the retainer pin 22 and provide spring force to return the trigger to its forward position after each shot, or depression of the trigger.

In the original AR-7 model rifle, the pivoting of the trigger during depression causes the hook 18 to come into the path of the rebounding hammer 6 following discharge. The hook 18 captures the hammer 6 by means of a sear release edge or notch 16 cut into the rearward section of the hammer. As previously explained, if the shooter were to hold the trigger 2 depressed hard enough, the hook 18 would not allow sufficient clearance for the hammer 6 to pass the hook and then be captured thereby. This is due to the fact that the hook and the trigger are integral, i.e., one cannot move relative to the other.

The present invention solves the short recoil problem by making the disconnector and the trigger into separate components that are coupled together, one being movable relative to the other. One embodiment of the invention is shown in FIGS. 2 and 3. The disconnector 10 is coupled to the trigger 2 by means of a pin 14. The trigger 2 is pivotable about a trigger pivot pin 4. In FIG. 2, the hammer is shown in a first rearward angular position in which the hammer is captured by the sear 26 formed by the nose (i.e., the forwardmost portion) of the trigger 2. The function of the sear is to hold the hammer in a captured rearward position until such time that the trigger is depressed, i.e., pulled. In FIG. 3, the hammer is shown in a second rearward angular position in which the hammer is captured by the disconnector hook 18. This hammer position is adopted during recoil. The function of the disconnector hook is to capture the hammer during its rebounding cycle. The disconnector will then hold the hammer until its capture can be transferred to the sear.

FIGS. 4-6 show three views of the trigger employed in the embodiment depicted in FIGS. 2 and 3. The trigger comprises a plate-like central portion 25 of constant thickness with a hole 32 drilled therethrough for the trigger pivot pin (not shown in FIG. 4). The trigger 2 incorporates a wider (i.e., wider than the central portion 25 is thick) portion 28 in its rearward section. All other dimensions mimic the original trigger in the AR-7 model rifle. This wider portion 28 allows for a recess or channel 30 to be machined lengthwise. The parallel walls on opposite sides of the recess in this wider portion each have a hole 32 drilled through it crosswise, these holes being equal in diameter and aligned (i.e., coaxial). The nose at the front of the trigger serves as a sear 26 that engages the hammer. A roll pin 42 is provided to limit the motion of the trigger to allow for a more comfortable trigger pull.

The recess in the top rearward portion of the trigger 2 allows a separate disconnector 10 (see FIG. 2) to be installed. FIGS. 7-9 show three views of the disconnector employed in the embodiment depicted in FIGS. 2 and 3. The disconnector 10 has dimensions that allow a bottom portion 38 (best seen in FIG. 7) thereof to slide in and along the recess 30 (indicated by dashed lines in FIG. 4) in the trigger 2. A retainer pin 14 (see FIG. 2) inserted in holes 32 is utilized to hold the disconnector in place. As best seen in FIG. 7, the disconnector 10 has a slot 12 machined lengthwise. This slot overlaps the holes 32 (see FIG. 4) in the rear portion of the trigger and has a length greater than the diameter of the retainer pin 14 (see FIG. 2) that couples the disconnector to the trigger. The retainer pin 14 (see FIG. 2) goes through the holes 32 (see FIG. 4) in the wider portion of the trigger and through the slot 12 (see FIG. 7) in the disconnector. When assembled, the disconnector is restrained against upward movement by the retainer pin 14 engaging the bottom edge of the disconnector slot 12, while the retainer pin 14 itself is limited in its ability to displace axially by the back wall and side plate of the receiver (not shown). However, the horizontal slot 12 allows the disconnector 10 the freedom to move back and forth by riding within the recess 30 machined in the rearward portion of the trigger 2, while being coupled to the trigger by the retainer pin 14.

In the retrofitted AR-7 model rifle disclosed herein, the retainer pin has dual functions: (1) coupling the disconnector to the trigger; and (2) serving as an anchor for the hammer spring. In the original (not retrofitted) AR-7 model rifle, the integral trigger/disconnector had two holes (seen in FIG. 1): one for the trigger pivot pin 4 and one for a second pin 22 that served the function of anchoring the hammer spring. Accordingly, in the trigger shown in FIG. 4, the axis of holes 32 in the wider portion 28 is situated precisely at the same distance away from the axis of the trigger pivot pin hole 40 (seen in FIG. 4) as the distance that separates the two holes in the aforementioned integral trigger/disconnector (see FIG. 1).

The last component in this trigger/disconnector assembly is a coil-type spring 20 (see FIG. 2), which is positioned within the recess of the trigger and behind the disconnector. Two projections 34 and 36 project in parallel from the rear of the disconnector 10, as best seen in FIG. 7. Referring again to FIG. 2, the spring 20 is seated in the space between the projections 34 and 36. The function of this spring is to urge the disconnector forward after each cycle. This arrangement allows the disconnector hook 18 to travel rearward in order to allow the hammer 6 to pass, during which rearward motion the spring 20 is compressed. The compressed spring 20 then urges the disconnector hook 18 back to its original position and causes it to capture the hammer 6, as shown in FIG. 3. This design mimics the original components of the AR-7 model rifle, but with moving parts to reduce the amount of force that is necessary to operate the rifle.

In the disclosed embodiment, the hammer 6, shown on a magnified scale in FIG. 10, may be substantially unchanged from the hammer employed in the unmodified AR-7 model rifle. One end of the hammer pivot pin (item 8 in FIG. 2) is inserted in a blind hole in the back wall of the receiver. As seen in FIG. 10, the hammer has a hole 44 that allows the hammer to slide onto the hammer pivot pin. When the side plate of the receiver is in place, the hammer pivot pin is blocked from falling out of the blind hole.

Still referring to FIG. 10, the hammer comprises a first sear release edge 28 and a second sear release edge 16. While the gun is cocked, the first sear release edge 28 is engaged by the sear 26 at the trigger nose (as seen in FIG. 2). Rotation of the hammer about the hammer pivot pin occurs at the urging of the hammer spring 21 when the hammer is released by the sear. The second sear release edge 16 of the hammer is engaged by the disconnector hook 18 (as seen in FIG. 3). During the rebounding cycle of the hammer, the hammer is captured by the disconnector when hook 18 latches behind the second sear release edge 16.

The procedure for retrofitting AR-7 model rifles in accordance with one embodiment of the invention will now be described.

In order to remove the integral trigger/disconnector from the receiver of a not yet modified AR-7 model rifle, one must first pull the trigger to allow the hammer to go to its forwardmost position. In this state, the rifle is said to be “uncocked”. At this point the sideplate screw can be removed and the sideplate can be lifted off the receiver. This exposes the trigger/disconnector mechanism of the rifle. At this point one can lift the trigger/disconnector off the trigger pivot pin and remove it from the receiver.

In order to assemble the trigger/disconnector mechanism seen in FIGS. 2 and 3, the disconnector spring 20 is placed into the recess in the rear portion of the disconnector. The disconnector 10 and its spring 20 are then placed into the recess 30 machined into a rearward portion of the trigger and the slot 12 in the disconnector must be aligned with the holes 32 (see FIG. 4) in the rearward portion of the trigger. Once this is accomplished, the retainer pin 14 can be installed. At this point the assembly sequence for the trigger/disconnector mechanism is complete.

In order to install the complete assembly into the receiver, the trigger/disconnector mechanism (with spring) is placed into the receiver, taking care that the hammer spring is captured by the protruding retainer pin that couples the disconnector to the trigger. The hammer spring can now be manually compressed and the pivot pin hole in the trigger must be aligned with the trigger pivot pin within the receiver. When this has been accomplished, the trigger/disconnector mechanism can be installed in the receiver by placing the trigger down onto the trigger pivot pin within the receiver. At this point the sideplate and its screw can be replaced, thereby completing the retrofit.

In accordance with the arrangement disclosed herein, a separate spring-loaded disconnector hook incorporated in the trigger/disconnector assembly is able to move to the rear when contacted by the hammer to allow the hammer to pass, and then quickly return to its forward position so as to capture the hammer. This can occur regardless of the position of the trigger. Previously the original components would not allow this to occur. As the trigger is released, the disconnector hook releases the hammer, and the hammer will begin to travel forward until it is captured once again by the trigger nose (i.e., the sear) engaging the sear notch of the hammer. The disclosed multiple-component assembly greatly reduces the amount of force required to operate the trigger mechanism of an AR-7 model rifle. This is an improvement because it eliminates the malfunction known as short recoil and enhances the function of the rifle.

The disclosed mechanism was designed to mimic the dimensions and function of the original AR-7 components. The wider portion of the trigger was designed to be installed within the receiver of an AR-7 model rifle with no modifications to the receiver. These design features allow the mechanical trigger/disconnector assembly to either be retrofitted in existing rifles or incorporated into current production.

While the invention has been described with reference to preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for members thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the invention without departing from the essential scope thereof. Therefore it is intended that the invention not be limited to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. 

1. An AR-7 rifle having a firing mechanism comprising: a hammer that pivots on a first pivot pin, a trigger that pivots on a second pivot pin; said trigger comprising a sear that holds said hammer in a first captured rearward position before the rifle is fired; a first spring that causes said hammer to pivot forward when said hammer is released from said first captured rearward position, and a disconnector coupled to said trigger in a manner that allows said disconnector to displace relative to said trigger, said disconnector comprising a hook that captures said hammer in a second captured rearward position during recoil after the rifle has been fired.
 2. The rifle as recited in claim 1, wherein said trigger comprises mutually parallel first and second walls and a recess therebetween, said disconnector being slidably seated in said recess of said trigger.
 3. The rifle as recited in claim 2, wherein said trigger comprises a first hole in said first wall and a second hole in said second wall, said first and second holes being aligned, and a pin mounted in said first and second holes, and said disconnector further comprises a base with a slot formed therein, said pin passing through said slot in said disconnector, said slot having a length greater than a diameter of said pin.
 4. The rifle as recited in claim 2, further comprising a second spring arranged to urge said disconnector to slide in a forward direction.
 5. The rifle as recited in claim 4, wherein said disconnector further comprises first and second rearward projections, said second spring being seated between said first and second projections.
 6. A method for retrofitting a rifle having an integral trigger/disconnector, comprising the steps of: removing the integral trigger/disconnector; and installing an assembly comprising a disconnector and a trigger in place of the integral trigger/disconnector, the disconnector being displaceable relative to the trigger.
 7. The method as recited in claim 6, further comprising the following steps performed before said installing step: coupling the disconnector to the trigger in a manner that allows the disconnector to displace relative to the trigger along an axis; and inserting a compression spring between a portion of the disconnector and a portion of the trigger, the spring exerting a force that urges the disconnector to displace relative to the trigger in one direction along the axis.
 8. The method as recited in claim 7, wherein the disconnector coupled to the trigger is substantially not rotatable relative to the trigger.
 9. The method as recited in claim 7, wherein said coupling step comprises inserting a portion of the disconnector in a recess formed in the trigger, passing a pin through circular holes in the trigger and through a slot in the disconnector, and securing the pin relative to the trigger.
 10. The method as recited in claim 6, wherein the rifle is an AR-7 model rifle.
 11. A method for installing a firing mechanism in an AR-7 model rifle, comprising the steps of: making a trigger having a rearward portion with a recess bounded on opposing sides by first and second walls, the first and second walls having first and second apertures respectively, the first and second apertures being aligned with each other; making a disconnector having a slot that will overlap the first and second apertures when a bottom portion of the disconnector is inserted into the recess with a predetermined positional relationship; inserting the bottom portion of the disconnector into the recess with said predetermined positional relationship; inserting a pin through the first and second apertures and the slot; and installing the coupled disconnector/trigger in a receiver of an AR-7 model rifle.
 12. The method as recited in claim 11, wherein the disconnector is designed to capture the rifle's hammer during recoil.
 13. The method as recited in claim 11, wherein the disconnector is designed to slide in the recess with substantially no rotation relative to the trigger.
 14. The method as recited in claim 11, further comprising the step of removing an integral disconnector/trigger from the receiver before said installing step.
 15. An assembly comprising: a trigger having a rearward portion with a recess bounded on opposing sides by first and second walls and having a flat bottom, said first and second walls having first and second apertures respectively, said first and second apertures having the same diameter and being aligned with each other; a disconnector having a bottom portion inserted in said recess in said rearward portion of said trigger, said disconnector having a slot that overlaps said first and second apertures, said slot having a length greater than said diameter of said first and second apertures, said disconnector comprising a bottom straight edge running parallel to a length direction of said slot; a retainer pin that passes through said first and second apertures and said slot, and projects beyond said first and second walls on respective sides of said rearward portion, and a coil spring seated at one end against a portion of said trigger and seated at the other end against a portion of said disconnector, said coil spring urging said disconnector to displace in said recess relative to said trigger. 